Concrete floor with embedded projecting truss



Jan. 31, 1967 G. D. RATLIFF, JR 3,300,932

CONCRETE FLOOR WITH EMBEDDED PROJECTING TRUSS Filed Sept. 17. 1964 INVENTO/i GEORGE D. RATL IFF, Jrv

-11 Attorney 3,300,932 CONCRETE FLOUR WITH EMBEDDED PROJECTING TRUSS George D. Ratliff, Jr., Churchill Borough, Pa., assignor to United States Steel Corporation, a corporation of Delaware Filed Sept. 17, 1964, Ser. No. 397,200 10 Claims. (Cl. 52339) This invention relates to a truss of improved construction. More particularly, it relates to a truss that has an improved load carrying capacity, while possessing a relatively small vertical dimension. Among other uses, the truss is well suited for supporting a concrete platform.

While a number of attempts have been made to improve on the design of the familiar I-beam to increase its load carrying capacity without substantially increasing its weight, beam and truss designs resulting from these efforts have had certain disadvantages. In some prior art Lbearns, an extremely deep web is provided in order to set the top and bottom flanges further apart and thereby increase the maximum bending moment that the beam will carry. However, to keep the weight of the beam down, the web is given a relatively small thickness, thus weakening the beam where the shear forces are the greatest and subjecting the beam to possible failure due to the large shear stresses that result therein. In the design of other types of support members, a truss is formed with two parallel T-shaped beams spaced far apart by a network of diagonal bars. While such trusses are eflicient load carriers, they are expensive to build, and their large vertical dimensions make them undesirable as ceiling or bridge supports in areas where a minimum vertical clearance is available.

It is therefore an object of my invention to provide a truss of improved design, eliminating the foregoing disadvantages of the support members discussed above.

A further object of my invention is to provide a truss having both an improved load carrying capacity, and a short vertical dimension for use in areas where a limited vertical clearance is available.

Another object of my invention is to provide a truss upon which a concrete platform may be easily built.

The attainment of these and other objects will appear more readily from the following description of my invention and the attached drawings in which:

FIGURE 1 is a side elevation of a truss partially embedded in and supporting a concrete platform;

FIGURE 2 is an enlarged cross-sectional view taken through line IIII of FIGURE 1; and

FIGURE 3 is an enlarged cross-sectional vie-w taken through line III-4H of FIGURE 1.

In FIGURE 1, a truss 2 is supported at its ends on beams B. The truss 2 includes a main beam 3, which has a web plate 4 of varying depth, a top horizontal flange plate 5, and flange plates 6 welded to the bottom of the web plate 4. The main beam 3 has a zig-zag shaped bottom edge 7, that includes at least one recess 8 having the shape of an inverted V with a vertex 9. Where only one such recess is present, as in the case of the truss shown in the drawings, this recess is preferably located midway between the support beams B.

Beneath the recess 8 is suspended a flat bar 12 that is bent into a V-shape and is welded at its ends 13 to flange plates 6, preferably at the lowest points of the zigzag bottom edge 7. A vertical strut 14 is fixed, preferably by welded joints, between the lowermost portion of the V-shaped bar 12 and the vertex 9 in the bottom edge 7 of the main beam.

The function of the V-shaped bar 12 is to provide increased resistance to tension forces at the middle portion of the truss, where these forces will be the greatest. The

United States Patent M Patented Jan. 31, 1967 bar 12, and the strut 14 provide a simpleand eflicient truss network beneath the main beam 3. Yet, the overall depth of the truss 2 is not appreciably increased, and the main beam 3 can be made relatively shallow, particularly above the strut 14. This permits the design of a rather thick web, able to withstand high shear forces, while effecting a relatively small increase in the overall weight of the truss. The end result is a truss that has a relatively high load-carrying capacity for its size and weight.

The truss 2 is particularly well suited for supporting a concrete floor. Most of the truss may be embedded in the floor if the forms for the concrete are laid on the bottom flange plates 6 of the truss. This unites the truss firmly with the floor without the use of special lugs or the like.

As shown in the drawings, the concrete form is made by laying corrugated metal sheets 20 on the bottom flange plates 6 and 6a of parallel adjacent trusses 2 and 211 (FIGURE 2). The end furrows of each corrugated sheet 20 overlap the end furrows of the adjacent sheets to make a continuous form upon which the concrete 22 may be poured (FIGURE 1). The sheets 20 do not have to be Welded or secured in any way to the trusses on which they are laid.

Concrete is poured over the corrugated sheets 20 to a thickness that will completely embed the web plates 4 and 4a and top flange plates 5 and 5a of the trusses 2 and 2a respectively, as shown in the sectional views of the floor in FIGURES 2 and 3. After the concrete 22 has been poured, the only parts of the trusses that will be extending beneath the floor will be the V-shaped bars 12 and 12a and the struts 14 and 14a. Thus, the truss construction shown and described herein leaves a high vertical clearance beneath the floor which it supports, in comparison with the elaborate, space-consuming trusses that have heretofore been used.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A truss comprising:

a main steel beam, said beam including a generally horizontal top flange, a generally vertical web, said web being of variable depth along its length, and a flange plate welded to the bottom of said web, said main beam having a recess in its bottom edge,

a steel bar extending lengthwise along a portion of the length of said main beam, the ends of said bar being welded to said bottom edge of the main beam and said bar having said ends disposed above its middle portion and being placed with said middle portion substantially in vertical alignment with the portion of the recess in said bottom edge closest to the top flange of said main beam, I

a substantially vertical steel strut extending upwardly from the said middle portion of said bar to the bottom edge of said main beam, and

welds connecting said strut to said bar and main beam.

2. A truss comprising:

a main beam, said beam including a generally horizontal top flange, a generally vertical web, said web being of variable depth along its length and a flange plate attached to the bottom of said web, said main beam having a recess in its bottom edge,

a bar extending lengthwise along a portion of the length of said main beam, the ends of said bar being connected to said bottom edge of the main beam and said bar having said ends disposed above its middle portion and being placed with said middle portion substantially in vertical alignment with the portion of the recess in said bottom edge closest to the top flange of said main beam, and

a substantially vertical strut extending upwardly from the said middle portion of said bar to the bottom edge of said main beam.

3. The truss of claim 2 wherein said recess in the bottom edge of said main beam is in the shape of an inverted V, the said strut extending to the said bottom edge at the vertex of said inverted V.

4. The truss of claim 2 wherein said bar is in the shape of an upright V, the said strut extending from said bar at the lowest portion of said upright V.

5. The truss of claim 4 wherein said recessed portion of the bottom edge of said main beam is in the shape of an inverted V, the said strut extending to the said bottom edge at the vertex of said inverted V.

6. A composite platform comprising:

parallel, spaced apart trusses, each of said trusses including:

a main steel beam having a generally horizontal top flange, a generally vertical web, said web being of variable depth along its length, and a flange plate welded to the bottom of said web, said main beam having a recess in its bottom edge,

a steel bar extending lengthwise along a portion of the length of said main beam, the ends of said bar being welded to said bottom edge of the main beam and said bar having said ends disposed above its middle portion and being placed with said middle portion substantially in vertical alignment with the portion of the recess in said bottom edge closest to the top flange of said main beam,

a substantially vertical steel strut extending upwardly from the said middle portion of said bar to the bottom edge of said main beam, and

welds connecting said strut to said bar and main beam,

a sheet of metal supported on the bottom flange plates of two adjacent trusses, and

a concrete platform supported on said sheet, the webs of said adjacent trusses being embedded in said platform.

7. A composite platform comprising:

parallel, spaced apart trusses, each of said trusses including:

a main beam that has a generally horizontal top flange, a generally vertical web, said web being of variable depth along its length, and a flange plate attached to the bottom of said web, said main beam having a recess in its bottom edge,

a bar extending lengthwise along a portion of the length of said main beam, the ends of said bar being connected to said bottom edge of the main beam and said bar having said ends disposed above its middle portion and being placed with said middle portion substantially in vertical alignment with the portion of the recess in said bottom edge closest to the top flange of said main beam, and

a substantially vertical strut extending upwardly from the said middle portion of said bar to the bottom edge of said main beam,

a sheet of metal supported upon the bottom flange plates of two adjacent trusses, and

a concrete platform supported on said sheet, the webs of said adjacent trusses being embedded in said platform.

8. The composite platform of claim 7 wherein said recessed portion of said bottom edge of the main beam is in the shape of an inverted V, the said strut extending to the said bottom edge at the vertex of said inverted V.

9. The composite platform of claim 7 wherein said bar is in the shape of an upright V, the said strut extending from said bar at the lowest portion of said upright V.

10. The composite platform of claim 9 wherein said recessed portion of said bottom edge of the main beam is in the shape of an inverted V, the said strut extending to the said bottom edge at the vertex of said inverted V.

References Cited by the Examiner UNITED STATES PATENTS 582,308 5/1897 Orr 52-339 X 678,380 7/1901 Davis 52-635 1,033,106 7/1912 Kahn 52339 X 1,686,910 10/1928 Frease 52226 FRANK L. ABBOTT, Primary Examiner.

A. C. PERHAM, Assistant Examiner. 

7. A COMPOSITE PLATFORM COMPRISING: PARALLEL, SPACED APART TRUSSES, EACH OF SAID TRUSSES INCLUDING: A MAIN BEAM THAT HAS A GENERALLY HORIZONTAL TOP FLANGE, A GENERALLY VERTICAL WEB, SAID WEB BEING OF VARIABLE DEPTH ALONG ITS LENGTH, AND A FLANGE PLATE ATTACHED TO THE BOTTOM OF SAID WEB, SAID MAIN BEAM HAVING A RECESS IN ITS BOTTOM EDGE, A BAR EXTENDING LENGTHWISE ALONG A PORTION OF THE LENGTH OF SAID MAIN BEAM, THE ENDS OF SAID BAR BEING CONNECTED TO SAID BOTTOM EDGE OF THE MAIN BEAM AND SAID BAR HAVING SAID ENDS DISPOSED ABOVE ITS MIDDLE PORTION AND BEING PLACED WITH SAID MIDDLE PORTION SUBSTANTIALLY IN VERTICAL ALIGNMENT WITH THE PORTION OF THE RECESS IN SAID BOTTOM EDGE CLOSEST TO THE TOP FLANGE OF SAID MAIN BEAM, AND A SUBSTANTIALLY VERTICAL STRUT EXTENDING UPWARDLY FROM THE SAID MIDDLE PORTION OF SAID BAR TO THE BOTTOM EDGE OF SAID MAIN BEAM, A SHEET OF METAL SUPPORTED UPON THE BOTTOM FLANGE PLATES OF TWO ADJACENT TRUSSES, AND A CONCRETE PLATFORM SUPPORTED ON SAID SHEET, THE WEBS OF SAID ADJACENT TRUSSES BEING EMBEDDED IB SAID PLATFORM. 